There are conventionally known robot controllers, each of which is connected to a plurality of robots in a mutually communicable manner and individually controls operations of each of the robots (refer, for example, to Japanese Patent Application Laid-open No. H3-182908).
Such a robot controller has, for example, first-in first-out buffers, each assigned to each of the robots, and can operate the robots in parallel by sequentially reading instructions directed to each of the robots stored in each of the buffers and by executing the instructions.
The robot controller can include, as controlled objects thereof, peripheral devices or the like of the robots, in addition to the robots themselves. In such cases, the robot controller treats each of the robots and the peripheral devices thereof as one controlled unit (hereinafter mentioned as “controlled group”), and controls operations of each of such controlled groups.
However, conventional robot controllers and robot systems provided therewith have insufficient synchronization accuracy between controlled groups, and therefore, are yet to be further improved in making the controlled groups perform coordinated operations in synchronization with each other.